Method of forming a key for an axial tumbler type lock



Sept. 2, 1969 W. J.- KERR METHOD OF FORMING A KEY ["08 AN AXIAL TUMULER TYPE LOCK Filed Dec. 9. 1966 F G. 6 34 32 l2 (I6 26 x r. V

Ilium r14 INVENTOR.

W1 LLIAM J. K ERR United States Patent 4 Claims The present invention relates to a novel and improved method of forming a key for an axial tumbler type look like that which is illustrated and described in U.S. Patent No. 3,267,706, granted to me on Aug. 23, 1966, and entitled Tamper-Proof Axial Tumbler-Type Lock.

The key which is produced by the method of the present invention is a special form of key. It is fully disclosed in my aforesaid Patent No. 3,267,706 and is also disclosed and claimed in my copending US. Patent application Ser. No. 600,551, filed on Dec. 9, 1966, now US. Patent No. 3,320,783, issued May 23, 1967 and entilted Key for an Axial Tumbler Type Lock. No claim is made herein to any novelty in the key per se, the novelty of the present invention residing solely in the method by which the key is formed.

For a comprehensive understanding of the present method of lock key manufactured or fabrication and the reason why other methods of forming the particular key are less expedient, it is deemed necessary that the construction, design and mode of operation of the particular lock which is operated by the key be understood. Such lock is a special form of axial tumbler type lock wherein the pin tumblers that are associated therewith and form a part thereof are arranged in an annular series around, and extend parallel to, the central longitudinal axis of the lock cylinder. The tumblers slide in bores and pass from the stationary part of the barrel assembly lock into the rotatable part of such assembly. They are transversely divided or split and are adapted to be longitudinally or axially displaced by the proper key for the lock against the resistance of helical compression springs in such a manner that their splits coincide with the joint or interfacial surface between the rotatable and stationary parts of the barrel assembly of the lock. For this purpose, the key which controls locking and unlocking of the lock is provided with an annular series of radially and outwardly extending pusher elements which correspond in number to, and are associated respectively with, the tumblers and define rearwardly facing shoulders. The latter are designed for engagement with the forward exposed ends of the tumblers and are disposed at different axially displaced positions which are commensurate with the distance to which the associated tumblers must be forced back into the tumblerreceiving bores in the rotatable and stationary parts of the barrel assembly of the lock so that all of the tumbler splits will coincide with said joint or interfacial surface between the rotatable and stationary parts of the barrel assembly to thus permit the rotatable part of said assembly to be turned by the key. To render such a lock tamper-proof, the front access opening which is adapted to receive the key and leads to the front exposed ends of the pin tumblers is provided with a shield in the form of a front wall, the shield having a central circular opening for projection of the cylindrical key shank into the lock cylinder. The shield is formed with an annular series of outwardly and radially extending slots which are in communication with the central opening, and are designed for register with a corresponding series of outwardly and radially extending fins on the key shank so that when the key is properly and rotationally oriented, the fins may be projected through the slots "ice to allow the key shank to enter the opening. A center post cooperates with a socket in the front end of the key shank to guide the key axially as it is being introduced into the lock opening. These radial fins constitute the aforementioned pusher elements. The radial slots in the protective shield are misaligned or out of longitudinal register with the pin tumblers so that when the key is first projected into the lock cylinder, the fins will be out of longitudinal register with the tumblers. Before these fins can be effective to depress the tumblers, it is necessary that the fins be projected forwardly beyond the plane of the protective shield and the key then turned about its longitudinal axis throughout a small angle to bring the fins into longitudinal register with the tumblers, after which the key may be further projected forwardly to depress the tumblers and thereby release the lock for unlocking purposes.

A key for actuating a lock of this general type must thus embody certain essential structural components including a cylindrical key shank which is capable of being projected endwise into the central opening in the protective shield of the lock and, therefore, must be formed with a pilot socket in its forward end to fit over the aforementioned center post. In addition, the shank must be provided with a series of radial fins properly spaced at angles commensurate with the angular positions of the slots in the protective shield so that all of the fins may be caused to register with all of the slots before the key can be projected forwardly into the lock cylinder. Furthermore, the forward edges of the fins must lie in different transverse planes with respect to the key shank so that the tumbler-depressing shoulders that are offered or formed thereby will be correctly positioned for proper respective tumbler displacement, the relative longitudinal positions of these shoulders, in effect, constituting the lock combination for the particular lock that is controlled by the key. Then again, some means for transferring torque from the key to the rotatable part of the barrel assembly of the lock must be provided, and in the present instance, this is accomplished by utilizing one of the radial fins on the key shank as a torque-applying member so that it may cooperate with a torque-receiving shoulder on said rotatable part of the barrel assembly after the key shank has been introduced into the lock cylinder and the tumblers depressed to their proper unlocking positions. Finally, the key shank must be provided with a suitable operating lever or handle by means of which torque may effectively be applied to the shank for easy turning movement thereof within the capabilities of the key operator. The particular method of the present invention affords a novel and extremely eflicient manner of forming a key possessing the aforementioned characteristics, the key that is formed by the method possessing qualities of strength, durability and efficiency of operation which are lacking when the key is formed by various other methods. The method of the present invention whereby such a key is formed is illustrated in the accompanying single sheet of drawings which forms a part of this specification.

In these drawings:

FIG. 1 is a perspective view of a length of extruded rod stock from which the shank and bittings of a key are formed;

FIG. 2 is a side elevational view of the key shank in one stage of its manufacture;

FIG. 3 is a sectional view taken longitudinally and sectionally through the structure shown in FIG. 2;

FIG. 4 is a plan view of a sheet metal stamping which comprises the key-operating handle for the key;

FIG. 5 is an exploded side elevational view of the handle and completed key shank preparatory to assembly thereof;

FIG. 6 is a sectional view taken centrally and longitudinally through a completely assembled key; and

FIG. 7 is a perspective view of the completely assembled key.

Referring now to the drawings in detail and in particular to FIG. 7 wherein a completely assembled key in accordance with the method of the present invention is illustrated in detail and designated in its entirety by the reference numeral 10, the key includes a cylindrical shank 12 having a relatively deep, thin-walled socket 14 in its forward end. The socket 14 is designed for telescopic reception over the pilot or center post that is associated with the lock to which the key 10 is adapted to be applied. Projecting radially outwardly from the wall of the socket 14 and disposed near the extreme forward end of the cylindrical shank 12 is a series of outwardly and radially extending fins 16 which are equally spaced around the outer cylindrical surface of the shank and, with the exception of one of the fins, namely, fin 160, are of equal radial extent and of equal thickness. The fin 16a is of greater radial extent than are the other fins and it is also of greater transverse thickness for a purpose that will be made clear presently. The forward radial end edge of the fin 16a lies in the transverse plans of the open rim 18 of the socket 14 while the forward radial edges of the regular fins 16 lie in different transverse planes spaced rearwardly from such rim 18 and constitute tumblerengaging shoulders so that when the key shank 12 is projected or shifted forwardly and endwise into the lock opening and the key turned to bring the various fins 16 into longitudinal register with the front ends of the lock tumblers, an additional slight forward projection of the key shank 12 in an axial direction will cause depression of the tumblers in the usual manner of lock operation. The rear edges of the various fins 16 and also of the fin 16a preferably lie in the same transverse plane.

The rear end of the shank 12 is bifurcated by means of a relatively deep, diametrically extending transverse notch 20. The latter receives therein the forward end region of a flat sheet metal torque-applying handle part in the form of a plate 22 of generally rectangular configuration. Such plate is formed by a stamping operation so as to provide generally rounded corners 24 and a circular opening 26 near the rear edge of the plate and by means of which the plate may be attached to a key ring or the like. The forward edge of the plate 22 is formed with a rectangular recess 30 of a width substantially equal to the diameter of the cylindrical shank 12. The plate 22 fits snugly within the notch 20 with the bottom of the recess 30 lying flush against the bottom of said notch 20. A locking pin 32 projects through a bore 34 in one side wall of the notch 20 and also projects through a small hole 36 (see FIG. 4) in the plate 22. One end of the pin 32 is received in a socket 38 in the other side wall of the notch 20. The plate 22 is thus securely anchored in the notch 20 in the shank 12 and the exposed portions of the plate constitute a wingtype handle by means of which torque may be applied to the shank 12 so that the key may be manually turned after it has been inserted in the lock cylinder.

As previously stated, the fins 16 present forward tumbler-engaging shoulders the function of which is to depress the pin tumblers when the shank 12 is operatively inserted into the lock cylinder. The fins 16 have no other function. On the other hand, the special radial fin 16a is a torqueapplying fin is that it is adapted to engage a torque-receiving shoulder that is provided on the rotatable part of the barrel assembly of the lock. For this reason, the fin 16a is of sturdier construction than are the fins 16, the necessary strength being afforded by making the fin 16a of greater transverse width than the fins 16 and also by causing it to be of slightly greater radial extent. All of the fins are equally spaced around the cylindrical outer surface of the shank 12 and preferably, but not necessarily, there are six of the tumbler-engaging fins 16 and one torqueapplying fin 16a.

The details of construction of the key 10 that is disclosed in FIG. 7 constitute no part of the present invention and, as hereinbefore indicated, no claim is made herein to any novelty that is associated with the same. Such a key constitutes the subject matter of my aforementioned copending patent application Ser. No. 600,551, and reference may be had to such application for a full understanding of the mode of operation of the key when it is applied to an axial tumbler type lock. The present application is concerned solely with the method by means of which the key 10 is formed. Such method will now be described in detail and subsequently claimed.

To form the key 10 according to the present invention, a length of shank stock 50 (see FIG. 1) is formed by a suitable extruding operation utilizing a metal which is susceptible to such extrusion operations. Alternatively, the shank stock 50 may be formed from cylindrical rod stock by a conventional broaching operation. In either event, the completed shank stock is in the form of an elongated rod of generally star shape configuration in transverse cross section and having an approximately cylindrical central core 52, along which there extends in parallelism a series of longitudinal flutes 54 which are six in number, and a single longitudinal flute 54a. All of the flutes are equally spaced around the circumference of the core 52. Each of the flutes 54 is in the form of a rib having flat sides 56 and a rounded crest portion 58, while the flute 54a is generally rectangular in transverse cross section. The radial extent and the width of the flutes 54 are comformable to the radial extent and width of the fins 16 that are associated with the finished key 10 and, similarly, the radial extent and width of the flute 54a is conformable to the radial extent and width of the fin 16a.

After the length of shank stock 50 has been formed, it is cut to length, which is to say that, for each key which is to be constructed, a length of the shank stock 50 is severed from the stock, the length, of course, being equal to that of a finished shank 12. Thereafter, the severed length of shank stock 50 is operated upon in a suitable milling machine or the like and the excess portions of the flutes 54 and 54a are removed from the core 52 so as to leave only the fins 16 and 16a. The resultant structure is illustrated in FIG. 2 wherein the portion of the length of shank stock from which the flutes 54 and 54a have been removed constitute the cylindrical shank 12 of the key 10.

Thereafter, the socket 14 is drilled in the front end of the shank 12 in order to produce the structure which is shown in FIG. 3. Alternatively, however, the socket 14 may be drilled in the shank 12 before the turning-down operation is performed upon the flutes 54 and 54a. It is also possible, according to the present method, to perform the turning-down operation on the elongated extruded shank stock 50 at several locations along the stock so as to produce a series of fin groups after which the rod may be severed to produce the individual shanks 12 which may then be operated upon to provide a socket 14 in each shank.

The next step in the production of the key 10 is to mill the notch 20 in the rear end of the shank 12, after which the diametrically extending bore 34 and the socket 38 may be drilled transversely through the shank by a single drilling operation. The flat plate 22, which is formed by a single stamping operation in order to produce both the plate outline and the opening 26 and the bore 34, is then installed in the notch 20 in the manner previously described and the locking pin 32 is then finally pressed or driven in place thus completing the key 10.

The invention is not to be limited to the method steps set forth above nor to the particular order in which they are preformed. For example, where the end results of any particular method step is complete in itself and is not dependent upon, or affected by, the performance of any other method stop, its performance may be resorted to at any time during the manufacture of the key where its result will contribute toward the progressive manufacture of the key. Obviously, it is within the purview of the invention to produce the notch 20 in the rear end of the cylindrical key shank 12 before the flutes 54 and 54a are turned down if desired. Therefore, irrespective of the sequence with which the method steps of the present invention are performed, the essential results sought for will remain substantially the same.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. The method for making a key for an axial tumbler type lock, said key having a cylindrical shank the forward end of which is provided with a cylindrical socket for reception over a pilot post associated with the lock, theforward end region of the shank having a series of equiangularly disposed radial fins the forward edges of which constitute tumbler-depressing shoulders, the rear endregion of the shank having a wing-type torque-applying handle thereon, said method comprising the steps of: (1) producing an elongated, linearly straight, length of key shank stock having a generally cylindrical core from which there project radially outwardly a series of equiangularly spaced flutes which conform in number and disposition to the number and disposition of said fins, extend longitudinally of the core, and are coextensive therewith;

(2) severing a key shank blank from said key shank stock;

(3) removing the excess material of the flutes on said blank so as to produce said fins by leaving them intact on the core of the blank;

(4) drilling said cylindrical socket in the forward end of the core of the blank; and

(5) aflixing a wing-type handle to the rear end of the core of said blank.

2. The method of making a key as set forth in claim 1 and wherein said method steps are performed sequentially and in the order named.

3. The method of making a key as set forth in claim 1 and wherein the step of producing the key shank stock is effected by an extrusion operation.

4. The method of making a key as set forth in claim 1 and wherein the step of removing the excess metal of the flutes is performed by a milling operation.

No references cited BERNARD STICKNEY, Primary Examiner 

1. THE METHOD FOR MAKING A KEY FOR AN AXIAL TUMBLER TYPE LOCK, SAID KEY HAVING A CYLINDRICAL SHANK THE FORWARD END OF WHICH IS PROVIDED WITH A CYLINDRICAL SOCKET FOR RECEPTION OVER A PILOT POST ASSOCIATED WITH THE LOCK, THE FORWARD END REGION OF THE SHANK HAVING A SERIES OF EQUIANGULARLY DISPOSED RADIAL FINS THE FORWARD EDGES OF WHICH CONSTITUTE TUMBLER-DEPRESSING SHOULDERS, THE REAR END REGION OF THE SHANK HAVING A WING-TYPE TORQUE-APPLYING HANDLE THEREON, SAID METHOD COMPRISING THE STEPS OF: (1) PRODUCING AN ELONGATED, LINEARLY STRAIGHT, LENGTH OF KEY SHANK STOCK HAVING A GENERALLY CYLINDRICAL CORE FROM WHICH THERE PROJECT RADIALLY OUTWARDLY A SERIES OF EQUIANGULARLY SPACED FLUTES WHICH CONFORM IN NUMBER AND DISPOSITION TO THE NUMBER AND DISPOSITION OF SAID FINS, EXTEND LONGITUDINALLY OF THE CORE, AND ARE COEXTENSIVE THEREWITH; 